Alloy



Patented July 3, 1934 UNITED STATES- 7 ALLOY Julius Aderer, New York, N. Y.

No Drawing. Application March 18, 1933, Serial No. 661,637

2 Claims.

The object of the invention is to provide a new alloy composed essentially of the precious metals, palladium and gold, and more particularly for the purpose of providing dental auxiliary ele- 5 ments for oral installation constituted of an alloy suitable for dental purposes shaped in the form of wires, bands, crowns, plates, etc. for appropriate application with reference to the dental condition in connection with which the auxiliary elements are to be used.

Heretofore; in the manufacture of such dental auxiliary elements it has been customary to use alloys in which the percentage of gold predomiv nates over the percentage of all other metals,

the gold being ordinarily alloyed with relatively large quantities of platinum of the order of 10% to 22%. Such alloys, while capable of use for their intended purposes, are necessarily expensive.

I have discovered that if the platinum is entirely omitted or permitted to be present only in small percentages of the order of less than 10%, and if a smaller amount of gold is alloyedwith a larger proportion of palladium, the alloy also 25 containing copper, some silver, and zinc, ensuperior alloy for dental purposes canbe produced at a cost which is approximately half that of the gold-platinum alloys.

In perfecting the composition of the new alloy it was necessary to bear in mind that the alloy must have a high fusing point which is essential for soldering. Although platinum has a higher fusion point than palladium, the fusion point of an alloy of palladium and gold is higher than that ofan alloy of platinum and gold. As an increase in the percentage of palladium in the alloy raises. its fusion point, and the palladium also possesses or imparts a desirable color, I use an excess of palladium over the amount of gold. Copper forms a part of the alloy to impart to it the quality of hardness, while zinc, imparts the necessary elasticity and toughness. The alloy possesses the requisite high fusing point, the quality of not losing color in the mouth, and sufiicient strength.

This alloy can be rolled from bars say fifteen inches long and one-fourth inch square to wires approximately one-sixteenth inch square. This can be accomplished without annealing and the 50 alloy does not show any fatigue during the rolling process. Any other comparable metal alloy will break under similar treatment. The property possessed by the new alloy is therefore valuable in saving labor. The new alloy can also be drawn through diamond draw plates to approximately twelve-thousandths of an inch, which is as fine as is required for dental uses. The wires or other forms may be annealed but in that case temperatures above 1200 F. and preferably of the order of 1800 F. or upwards should be employed. This treatment softens the wire and takes the springiness or elasticity out of it. After such annealing the wire can be readily shaped and the dental attachments soldered thereto. Thereupon the dentist heats the product to about 1000 F. and allows it to cool slowly. This treat ment tempers the finished product. The wires made of the new alloy possess a high degree of lcglastticity and will not snap unless very sharply The new alloy is easily produced, the zinc, copper, and silver being placed in a furnace or crucible, usually in the form of small pellets, the zinc first, copper on top, and then silver. The gold and palladium are first thoroughly mixed in a separate crucible and the mixture is rolled out and then put into the crucible containing the zinc, copper, and silver.

A formula which I have found extremely satisfactory is: gold approximately 33 parts, silver so approximately 5 parts, palladium approximately 39 parts, copper approximately 22 parts, and zinc approximately 4 parts. The amount of gold may very between the limits of 30 to 40 parts, the palladium between about '35 to 50 parts, the 5 copper between about 18 to 30 parts, the silver about to 8 parts, and the zinc between about 2 to 6 parts. The amount of. silver may be increased, for instance, as set forth in myPatent No. 1,924,097, dated August 29, 1933, to a'pproximately between 10 to 23 parts. The silver is present in the new alloy in order to obtain a more homogeneous alloy, but with careful manipulation it is possible to obtain an alloy of equal value withoutusing silver at all.

The addition of some platinum not in excess of 10% will not defeat the advantage of the new alloy, though it is preferred to have no platinum present. In other words I desire it to be understood that if some platinum, not inexcess of 109 10%, is added, the presence of such material would not alter the essential character of my 'new alloy. 1

.The melting point of my new alloy is about 2085" F. The Brinell hardness in the softened state is about 202; after tempering at 860 F., and cooling it slowly in thirty minutes, the alloy showeda Brinell hardness of about 426. The tensile strength of this wire, when tempered, is as high as 191,000 P unds per square inch. When no it is annealed or softened, the tensile strength is only between 88,000 and 103,600, showing an elongation between 25 and 28 in 2 inches, whereas in the hardened state the elongation is only from 2 to 5.

This new alloy combines with a high fusing point, which is very desirable, an elastic quality of a high degree.-

I claim:

1. An alloy constituted of approximately 30 to 40 parts gold, approximately 35 to 50 parts palla- JULIUS ADERER. 

